A ship of 4000 tonne displacement has its centre of gravity 6 m above the keel. Find the new displacement and position of the Centre of gravity when masses of 1000, 200, 5000 and 3000 tonne are added at positions 0.8, 1.0. 5.0 and 9.5 m above the keel.

 

A ship of 4000 tonne displacement has its centre of gravity 6 m above the keel. Find the new displacement and position of the Centre of gravity when masses of 1000, 200, 5000 and 3000 tonne are added at positions 0.8, 1.0. 5.0 and 9.5 m above the keel.

Reference: REED'S NAVAL ARCHITECTURE FOR MARINE ENGINEERS (4^th edition), Exercise – 4.1

Solution:

Mass (ton)	KG (m)	Moment (keel)
4000	6	24000
1000	0.8	800
200	1	200
5000	5	25000
3000	9.5	28500
∑ = 13200		∑ = 78500

 

New KG = Total moment/Total mass

                 = 78500/13200

                 = 5.947 m